Democratic presidential frontrunner Hillary Clinton said on Monday that putting American combat troops on the ground in Syria or Iraq to fight the Islamic State group was a "non-starter."

"Well, at this point I cannot conceive of any circumstances where I would agree to do that because I think the best way to defeat ISIS is, as I've said, from the air which we lead, on the ground, which we enable, empower, train, equip and in cyberspace where, don't forget, they are a formidable adversary online," Clinton said, according to AFP.